The invention relates to a device and a method of injecting a flexible intraocular lens which is ready to use, that is, ready to be implanted by injections through an incision formed in the wall of a patient's eye.
Flexible intraocular lenses are useful, for example, in a cataract operation in order to restore sight by a surgical procedure, which inserts into the eye such intraocular lens, which replaces the natural lens that has become opaque due to the cataract.
Flexible intraocular lenses are often made of hydrophilic material(s) such as, for example, hydrogel, acrygel or acrylic (the latter term deviating from its normal meaning), which materials are PMMA (polymethylmethacrylate) and/or HEMA (hydroxymethylmethacrylate), hydrated to more than 16%, in particular between 24% and 28%. U.S. Pat. No. 4,787,904 describes various examples of materials that may be used to produce hydrophilic lenses. These lenses need to be kept in a hydrated state for conservation.
Flexible intraocular lenses can also be made from silicone materials, having a higher refractive index than hydrophilic materials, or hydrophobic acrylic materials with low glass transition temperatures. The latter materials are desirable because they typically have a high refractive index and lenses made from them unfold more slowly and more controllably than silicone lenses. U.S. Pat. No. 7,157,538 describes such a high refractive index, acrylic material used for making hydrophobic flexible intraocular lenses.
Flexible intraocular lenses have the advantage of being able to be folded, allowing them to pass through incisions in the eye of small dimensions. However, the problem arising with these flexible lenses is precisely that of folding and manipulating them at the moment of the surgical act. U.S. Pat. No. 4,787,904 proposes to conserve a hydrophilic lens in a folded state in the injection device while being immersed in a conserving solution, the whole assembly being contained in a flexible packaging pocket. However, this method may not be used in practice, since a lens which has remained folded for a long period may retain a shape memory of the folded state and therefore does not regain its unfolded, functional shape after implantation.
As a result, hydrophilic lenses up to now have been conserved flat in sterilized rigid containers of conserving solution. At the moment of the surgical act, the surgeon removes the lens using a pincer, folds it (optionally with the aid of a folding device) or places it in a folding cartridge or in an injector and injects it into the eye. These manipulations are relatively complex and delicate, increasing the risk of contamination and damage to the lens.
U.S. Pat. No. 6,386,357 discloses a soft intraocular lens-folding device comprising a base member with a tapered slide groove portion, and a movable member comprising an elastically bendable pair of legs and a common base connecting the pair of legs. A soft intraocular lens is introduced in the lens-receiving portion of the movable member, the lens being clamped by wall portions. The lens is folded by moving the movable member into the groove portion in the base member, forcing the legs of the movable member to be drawn near to one another. This document does not disclose any means for injecting the folded lens.
U.S. Patent Publication No. 2005182419 discloses an injector for an intraocular lens comprising an injector housing with an intraocular lens disposed in the housing. The injector further comprises a lens carrier, which, in response to an actuator, engages and moves the lens within a narrowing injection nozzle in order to fold the lens. A plunger is then used to advance the folded lens and inject it into a patient's eye. Here, folding and injection of the lens cannot be achieved by a single, continuous movement of a plunger, adding complexity to the surgical procedure.
What has been needed, and heretofore unavailable, is an injector configured to accept an intraocular lens, the injector also configured to allow the lens and injector to be sterilized as one unit. In this manner, the lens is preloaded into the injector, the injector may be filled with a suitable fluid, and then subjected to a sterilization process. The injector should be able to withstand the sterilization process without leaking any fluid from a lens containing portion of the injector, thus ensuring that the lens stays immersed in the fluid once the sterilization process is completed and the injector/lens assembly is packaged and stored. In this way, the injector/lens assembly is ready for use by a surgeon without the need to hydrate or rehydrate the intraocular lens, nor load the lens into the injector, prior to surgery. The present invention fulfills these, and other needs.